The invention relates to the field of intravascular catheters, and particularly to a catheter suitable for angioplasty and/or stent deployment, and the like.
In percutaneous transluminal coronary angioplasty (PTCA) procedures a guiding catheter is advanced in the patient""s vasculature until the distal tip of the guiding catheter is seated in the ostium of a desired coronary artery. A guidewire is first advanced out of the distal end of the guiding catheter into the patient""s coronary artery until the distal end of the guidewire crosses a lesion to be dilated. A dilatation catheter, having an inflatable balloon on the distal portion thereof, is advanced into the patient""s coronary anatomy over the previously introduced guidewire until the balloon of the dilatation catheter is properly positioned across the lesion. Once properly positioned, the dilatation balloon is inflated with inflation fluid one or more times to a predetermined size at relatively high pressures so that the stenosis is compressed against the arterial wall and the wall expanded to open up the vascular passageway. Generally, the inflated diameter of the balloon is approximately the same diameter as the native diameter of the body lumen being dilated so as to complete the dilatation but not overexpand the artery wall. After the balloon is finally deflated, blood flow resumes through the dilated artery and the dilatation catheter and the guidewire can be removed therefrom.
In such angioplasty procedures, there may be restenosis of the artery, i.e. reformation of the arterial blockage, which necessitates either another angioplasty procedure, or some other method of repairing or strengthening the dilated area. To reduce the restenosis rate of angioplasty alone and to strengthen the dilated area, physicians now normally implant an intravascular prosthesis, generally called a stent, inside the artery at the site of the lesion. Stents may also be used to repair vessels having an intimal flap or dissection or to generally strengthen a weakened section of a vessel or to maintain its patency. Stents are usually delivered to a desired location within a coronary artery in a contracted condition on a balloon of a catheter which is similar in many respects to a balloon angioplasty catheter, and expanded within the patient""s artery to a larger diameter by expansion of the balloon. The balloon is deflated to remove the catheter and the stent left in place within the artery at the site of the dilated lesion. See for example, U.S. Pat. No. 5,507,768 (Lau et al.) and U.S. Pat. No. 5,458,615 (Klemm et al.), which are incorporated herein by reference. Thus, stents are used to keep open a stenosed vessel, and strengthen the dilated area by remaining inside the vessel. Instead of first using one catheter to dilate the body lumen and a second catheter to deploy the stent after the dilatation, the stent may be mounted on a balloon catheter and deployed at the same time the balloon is inflated to dilate the stenotic region.
Conventional balloon catheters for intravascular procedures, such as angioplasty and stent delivery, frequently have relatively stiff proximal shaft sections to facilitate advancement of the catheter within the patient""s body lumen and a relatively flexible distal shaft sections to facilitate passage through tortuous anatomy such as distal coronary and neurological arteries without damage to the luminal wall. Typically, there is an intermediate shaft section or junction between the relatively stiff proximal shaft section and the relatively flexible distal shaft section which provides a transition between the proximal shaft section and less flexible than the distal shaft section.
A variety of shaft or junction designs have been utilized to enhance the transition between the more stiff proximal shaft and the more flexible distal shaft sections. However, what has been needed is a catheter with enhanced transition and improved overall and distal trackability, as well as improved inflation/deflation performance. The present invention satisfies these and other needs.
The invention is generally directed to an intraluminal catheter system with an improved transition between a proximal shaft portion and a more flexible distal shaft portion. The improvement provides enhanced flexibility and kink-resistance, thus, facilitating advancement through tortuous anatomy. The present catheters may be used for either or both angioplasty and stent deployment.
The catheters of the present invention includes an elongated shaft having proximal and distal shaft sections, an inflatable member disposed on the distal shaft section and having proximal and distal ends and an interior chamber. A guidewire receiving lumen extends along at least a portion of the proximal shaft section and at least a portion of the distal shaft section and extends distally to the shaft distal end. An inflation lumen extends along at least a portion of the proximal shaft section and at least a portion of the distal shaft section to a point proximal to a shaft distal end and is in fluid communication with the inflatable member interior chamber. The proximal shaft section has a plurality of tubular members forming non-concentric lumens with at least one lumen forming at least a portion of the guidewire receiving lumen and at least one lumen forming at least a portion of the inflation lumen.
The proximal shaft section has multiple non-concentric lumens with at least one lumen forming at least a portion of the guidewire receiving lumen and at least one lumen forming at least a portion of the inflation lumen. In one embodiment, there are at least three non-concentric lumens while in another embodiment there are at least four such lumens. The distal shaft section includes an outer tubular member with a proximal extremity disposed about and securely attached to a distal extremity of the proximal In one embodiment, the proximal extremity of the outer tubular member forms a seal with at least a portion of each of the proximal shaft lumens.
In a presently preferred embodiment, all of the proximal shaft lumens except the guidewire lumen are non-guidewire receiving lumens circumferencially disposed about the guidewire receiving lumen. Preferably, the multiple non-concentric lumens are disposed such that the transverse centers of the non-guidewire receiving lumens form a triangular arrangement.
Preferably, the non-guidewire lumens are inflation lumens usable in the delivery of all fluids, such as inflation fluids, to and from the catheter. In a preferred embodiment, the non-guidewire lumens are longitudinally set apart with the guidewire receiving lumen extending distally beyond the non-guidewire lumens.
In one embodiment, the distal shaft section includes an inner tubular member extending along at least a portion of the outer tubular member to the shaft distal end. The inner tubular member forms at least a portion of the guidewire receiving lumen in the distal shaft section and defines with the outer tubular member at least a portion of the inflation lumen.
In another embodiment, the guidewire receiving lumen includes a proximal guidewire receiving lumen, and a distal guidewire receiving lumen formed by the inner tubular member in the distal shaft section, with the two guidewire lumens being in fluid communication with one another.
In an embodiment, a proximal extremity of the inner tubular member is sealingly disposed about a distal extremity of the proximal guidewire lumen and forming a junction therebetween.
In another embodiment, the inner tubular member extends proximally within the proximal guidewire receiving lumen to the shaft proximal end.
In a presently preferred embodiment, a reinforcing member, such as a coil, extends within at least a portion of the guidewire receiving lumen, preferably, within at least a portion of the guidewire receiving lumen extending in the distal shaft section.
The outer tubular member can be tapered the distal direction. The tapering of the outer tubular member can be continuous or in steps.
The catheter of the present invention provides an improved design with superior pushability in the proximal shaft section, a greater degree of flexibility in the distal shaft section for more distal advancement of the catheter and an intermediate shaft section with a smoother, more flexible transition between the proximal and distal shaft sections.
Additionally, the catheters of the present invention provide enhanced deflation/inflation performance as well as improved reliability, as for example, little or no inner member collapse. Furthermore, the present invention provides a more balanced distribution of the inflation/deflation lumens, hence, improved guide wire movement within the guide wire lumen.